1. Field of the Invention
The present invention relates in general to a drive device for a portable minidisk player and, more particularly, to an improved structure in such a drive device for simplifying construction, reducing cost, and increasing compactness.
2. Description of the Related Art
Typical portable minidisk players generally use microcompact disks. Conventionally, such portable minidisk players play the microcompact disks in the order they are loaded by rotating the loaded disk and picking up information from the rotating disk by a pickup. To facilitate carrying the minidisk players, these players should be light, thin, small, simple, and compact.
With reference to FIGS. 1, 2a and 2b, there is shown a disk loading part of a typical drive device for a portable minidisk player. In these figures, the front loading operation or the disk loading operation of the typical device is represented.
In FIG. 1, the cartridge guide bracket for receiving a minidisk 1 is designated by the numeral 2. The guide bracket 2 is provided with a pair of projections 3 on each side. The pair of projections 3, spaced out at an interval, penetrate slant slits 5 of a power transmission rack 4 and in turn are inserted into slits 8 of a guide panel 7. The two guide panels 7 are fixedly mounted on opposed sides of a deck 6. One guide panel 7 is shown in FIG. 1. The power transmission rack 4 engages and cooperates with a gear train 9. The drive spur gear of the gear train 9 engages a worm gear 11 mounted on the output shaft of a loading motor 10.
When the cartridge guide bracket 2 is placed at the front disk inlet of the deck 6 and receives a new disk 1 therein as shown in FIG. 2a, the insertion of disk 1 is sensed by a limit switch (not shown). The limit switch, when sensing the disk insertion, outputs a disk sensing signal to start the loading motor 10. The rotational force of the loading motor 10 is transmitted to the power transmission rack 4 through the worm gear 11 and the gear train 9. The power transmission rack 4 linearly moves rightward in FIG. 2a, thereby starting the disk loading operation.
When the power transmission rack 4 starts its rightward linear movement as shown in FIG. 2a, the projections 3 of the guide bracket 2 gradually linearly move in the horizontal sections of slits 8 of the guide panel 7. When the center of the disk 1 precisely coincides with the center of a turntable 12, the projections 3 of the guide bracket 2 reach the vertical sections of slits 8 of the panel 7 and, at the same time, descend along those vertical sections until seated on the bottoms of the vertical sections. As briefly described, the cartridge guide bracket 2, having the disk 1, moves back and down in the minidisk player under the guide of both slant slits 5 of the power transmission racks 4 and the slits 8 of the guide panels 7. The slits 5 and 8 cooperate with each other, and finish the disk loading operation.
When unloading the disk 1, the loading motor 10 rotates in the opposite direction, and the power transmission racks 4 move leftward in FIG. 2b. The leftward linear movement of the power transmission racks 4 causes the projections 3 of the guide bracket 2 to be pushed up by the slant slits 5 of the racks 4 and in turn to ascend along the vertical sections of the slits 8 of the guide panels 7. The projections 3 of the guide bracket 2, thereafter, move in the horizontal sections of the slits 8 of the guide panels 7, thus the cartridge guide bracket 2 reaches the front disk inlet of the player as shown in FIG. 2a. The disk unloading operation is thus finished.
FIG. 3 is a sectional view of a pickup drive part of the typical minidisk player drive device. As shown in this drawing, the disk 1 is precisely seated on the turntable 12 as a result of the above disk loading operation. Turntable 12 is rotated by a spindle motor 13. When the disk 1 is precisely seated on the motor-driven turntable 12, a pickup 16 starts the operation of picking up the information of the disk 1. This pickup 16 is driven by a lead screw 15. The lead screw 15 is rotated by the rotational force of a pickup drive motor 14 that is placed at a side of the spindle motor 13. To transmit the rotational force of the pickup drive motor 14 to the lead screw 15, a plurality of gears are arranged between and engaged with the output shaft of the motor 14 and the lead screw 15. In this case, the pickup 16 in its initial position should be placed above the center of the disk 1.
However, it has been noted that the typical device for driving the portable minidisk player has the following problems.
The typical minidisk player drive device should have at least two motors, that is, the loading motor 10 and the pickup drive motor 14, for carrying out the disk loading/unloading operation and driving the pickup 16 respectively. With the two motors, the cost of the minidisk player is increased. The expensive cost deteriorates the competitive power of the products.
The above drive device uses the gear train 9 for linear reciprocation of the power transmission rack 4, so that the loading motor 10 should use a large capacity and large-sized motor. The gear train 9 also occupies considerable space in the drive device and, as a result, enlarges the size of the player. This directly runs counter to the recent trend of compactness of the portable minidisk players.